1. Technical Field
The present invention relates to a noise suppressing apparatus and a noise suppressing method that calculate a suppression coefficient for suppressing noise of an input signal.
2. Description of the Related Art
A hands-free telephone system is used as a video conference system etc. This telephone system includes a noise suppressing apparatus that suppresses noise contained in a signal collected by a microphone. This telephone system is installed in various environments, but when the telephone system is installed in an environment where background noise is large, the clarity of sound during a telephone call undesirably decreases. Furthermore, in recent years, this telephone system has been installed in cars, in which the background noise has a stronger influence. Therefore, a noise suppressing apparatus that has high noise suppression performance and achieves high-quality sound is desired.
For example, T. Lotter et al., “Noise reduction by maximum a posteriori spectral amplitude estimation with supergaussian speech modeling”, IWAENC 2003, pp. 83-86 (hereinafter referred to as “NPL 1”) and Japanese Patent NO. 4542790 (hereinafter referred to as “PTL 1”) propose a noise suppressing apparatus and a noise suppressing method that calculate a suppression coefficient for suppressing noise. NPL 1 and PTL 1 propose a noise suppressing apparatus and a noise suppressing method that calculate a suppression coefficient for suppressing noise while keeping the amount of computation low by utilizing MAP estimation and Bayes' theorem.